Maegi

The bloodmagic of maegi is hated, mistrusted, and forbidden by the Dothraki, who claim that the maegi lie with demons and come to men in the dark of night to suck life and strength from their bodies. They may sometimes go so far as to kill anyone even assumed to be maegi, as to prevent her from cursing them with evil magic. Maegi often show a remarkable capability of telling one's future, usually from a drop of blood.[3]